Prior art techniques of measuring mechanical shaft angle are numerous. One such method is to use an electromechanical device generically called an resolver type position transducer. A typical resolver type position transducer would be comprised of two disks, one which rotates relative to the other. One of the disks would house the stator windings (does not move) while the other houses the rotor winding.
Generally, two separate windings are physically arranged on the stator so that electrical signals from these two windings are coupled in quadrature onto the rotor windings of the second member. The magnitude of the coupling for each of these winding pairs is dependent upon the mechanical shaft angle present between the stator and the rotor. Very often, numerous winding poles are configured into the device so that an electrical/mechanical geardown ratio is achieved. For example, a mechanical rotation of 180 degrees might correspond to an electrical phase shift of 18,000 degrees if the geardown ratio were 100 (corresponding to 200 pole pairs).
The relation between the input and output signals of a resolver type position transducer are related to the geometry of the resolver type position transducer stator and rotor windings. Since this geometry changes as the rotor changes its position, then it becomes possible to extract positional information by comparing the output and input signals of resolver type position transducer to create an output known as a synchro signal. Various methods of accomplishing this measurement to provide the synchro signal have been devised using both amplitude and phase modulation techniques and are known as digital to synchro converters.
In digital to synchro converters that currently exist, at least two Multiplying Digital to Analog Converters (MDACs) are used for each synchro. When multiple synchro outputs are required, this converter is both costly for the materials as well as complex for manufacturing and operation. It would be beneficial for a simpler design which is low cost.